RRC Signalling for fast HS-DSCH serving cell change

ABSTRACT

When a Universal Terrestrial Radio Access Network (UTRAN) receives an indication on Layer 3 (L3) (an L1/L2 indication is also possible) from the User Equipment (UE) that it is switching the High Speed-Data Shared Channel (HS-DSCH) reception to another cell in the active set (AS), the UTRAN sends a reconfiguration message to the UE via the target cell using a pre-configured configuration that UE has taken into use. The message can only include an indication that the pre-defined configuration can be used further by the UE or that a complete new configuration is to be used, e.g., using new HARQ info or even a hard handover (HHO) to another frequency. After receiving the configuration message, the UE responds with a normal reconfiguration complete message.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/691,036 filed on Jun. 15, 2005.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to mobile communications and, moreparticularly, to signaling during a handover.

2. Discussion of Related Art

Although the invention arose in the context of the downlink packet datatransmission in UMTS (Universal Mobile Telecommunications System)Terrestrial Radio Access, it is not limited thereto and the explanationsthat follow should be understood in a way that does not limit theinvention to that context. High Speed Downlink Packet Access (HSDPA) isa feature included in Release'5 3GPP specifications and is furtherenhanced in Release 6 with the support of fractional Dedicated PhysicalChannel (DPCH), called F-DPCH, and the support of Signalling RadioBearer mapping on the High Speed Downlink Shared Channel.

The invention addresses but is not limited to the Release 7 HSDPAimprovement under discussions, which aims to speed up the handover andserving HS-DSCH cell change processes with HSDPA especially with realtime applications, such as VoIP (Voice over Internet Protocol). One ofthe proposals has been presented in R1-050324 (Lucent) 3GPP TSG-RAN1meeting # 40bis, 4-8 Apr. 2005, Beijing, China, 2005.

As expressed in R1-050324, the UTRAN pre-configures the BTS (BaseTransceiver Station or “Node B” for a UE initiated cell change. Afterthe UE has sent the layer 1, layer 2 or layer 3 indication e.g. RRC(Radio Resource control) layer measurement report indicating the cellchange, the UE starts listening to the target cell. The UE can listen toboth the source and target cells simultaneously (R1-050324).

The present invention addresses but is not limited to the L3 signallingscheme for the HS-DSCH serving cell change solutions where the UEchanges the HS-DSCH reception to the other “pre-configured” cell afterindicating the cell change in L1/2/3 signalling to the UTRAN. The priorart solution (R1-050324) does not solve the problem of how the UTRAN(RNC) is made aware (especially when Bi-casting is utilized by the UTRANin the source and target cells) that the change is successful or givepossibilities for UTRAN conform the cell change or further reconfigurethe existing pre-configured configuration. In addition, the proposedscheme requires protocol interaction to keep RRC in correct state.

BRIEF SUMMARY OF THE INVENTION

Although an object of the present invention is to overcome theabove-described problems, it is not limited to the specific problemsdescribed.

According to a first aspect of the present invention, a method forexecution in a radio access network (RAN) comprises the steps ofreceiving a signal indication from a user equipment (UE) that it wantsto switch reception of a high-speed data flow from a source cell toreception from another, target cell, and in response thereto, switchingtransmission of said data flow to the UE from said source cell to saidtarget cell, sending to the UE a reconfiguration message via said targetcell a message containing an indication that informs the UE to keep apre-configured configuration or containing an indication of a new orpartly new configuration, which the RAN prefers over the pre-configuredconfiguration, and in response thereto, receiving from the UE areconfiguration complete message.

In further accord with the first aspect of the invention, the indicationof a new or partly new configuration, which the RAN prefers over thepre-configured configuration, contains possible new neighboring cellswhich UE may consider for subsequent switch of the reception of ahigh-speed data flow.

In still further accord with the first aspect of the invention, themethod further comprises the step of waiting a predetermined period oftime between said receiving said signal indication from said UE that itwants to switch reception of said high-speed data flow and saidswitching said transmission of said data flow from said source cell tosaid target cell.

Further according to the first aspect of the invention, the methodfurther comprises the step of also sending the reconfiguration messagevia said source cell so that said reconfiguration message is bi-cast tosaid UE from both said source cell and said target cell.

Still further in accord with the first aspect of the present invention,a computer program stored in coded form on a computer readable medium isprovided for facilitating and/or executing any one or more of the abovementioned steps in said RAN. Moreover, an integrated circuit may beprovided for installation in said RAN for carrying out two or more ofthe steps according to the first aspect of the present invention.

According to a second aspect of the invention, a radio access networkcomprises a device or means for receiving a signal indication from auser equipment that it wants to switch reception of a high-speed dataflow from a source cell to reception from another, target cell, a deviceor means responsive to said signal indication from said user equipmentfor switching transmission of said data flow to the user equipment fromsaid source cell to said target cell, a device or means for sending tothe user equipment a reconfiguration message via said target cell amessage containing an indication that informs the user equipment to keepa pre-configured configuration or containing an indication of a new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, and for receiving, in response to saidreconfiguration message, a reconfiguration complete message from theuser equipment.

In further accord with the second aspect of the invention, theindication of a new or partly new configuration, which the radio accessnetwork prefers over the pre-configured configuration, comprisespossible new neighboring cells which UE may consider for subsequentswitch of the reception of a high-speed data flow.

In still further accord with the second aspect of the present invention,the radio access network further comprises a device or means for waitinga predetermined period of time between said receiving said signalindication from said user equipment that it wants to switch reception ofsaid high-speed data flow and said switching said transmission of saiddata flow from said source cell to said target cell.

In yet further accord with the second aspect of the present invention,the device or means for sending the reconfiguration message to the userequipment is also for sending the reconfiguration message via the sourcecell so that the reconfiguration message is bi-cast to the UE from boththe source cell and the target cell.

Still further in accord with the second aspect of the present invention,an integrated circuit is provided for installation in a network elementof said radio access network wherein said integrated circuit embodiestwo or more of the elements of said radio access network according tothe second aspect of the invention.

According to a third aspect of the invention, a method for execution inuser equipment comprises the steps of sending a signal indication to aradio access network that the user equipment wants to switch receptionof a high-speed data flow from a source cell to reception from another,target cell, receiving an acknowledgement message from the radio accessnetwork, switching reception of said data flow from said source cell tosaid target cell after a predetermined time period after receipt of saidacknowledgement message, receiving a reconfiguration message from saidradio access network containing an indication that informs the userequipment to keep a pre-configured configuration or containing anindication of a new or partly new configuration, which the radio accessnetwork prefers over the pre-configured configuration, and in responsethereto, sending a reconfiguration complete message to the radio accessnetwork.

In further accord with the third aspect of the present invention, theindication that informs the user equipment to keep a pre-configuredconfiguration or contains an indication of a new or partly newconfiguration, which the radio access network prefers over thepre-configured configuration comprises new neighboring cells which UEmay consider for subsequent switch of the reception of a high-speed dataflow.

According still further to the third aspect of the present invention, anintegrated circuit is provided for carrying out two or more of the stepsaccording to the third aspect of the invention in any combination and inany order.

Still further in accord with the third aspect of the present invention,a computer program stored in coded form on a computer readable medium isprovided for executing the above mentioned steps in said user equipment.

According to a fourth aspect of the present invention, user equipmentcomprises a device or means for sending a signal indication to a radioaccess network that the user equipment wants to switch reception of ahigh-speed data flow from a source cell to reception from another,target cell, a device or means for receiving an acknowledgement messagefrom the radio access network, a device or means for switching receptionof said data flow from said source cell to said target cell after apredetermined time period after receipt of said acknowledgement message,and device or means for receiving a reconfiguration message from saidradio access network containing an indication that informs the userequipment to keep a pre-configured configuration or containing anindication of a new or partly new configuration, which the radio accessnetwork prefers over the pre-configured configuration, and in responsethereto, for sending a reconfiguration complete message to the radioaccess network.

In further accord with the present invention, the indication thatinforms the user equipment to keep a pre-configured configuration orcontains an indication of a new or partly new configuration, which theradio access network prefers over the pre-configured configuration,comprises possible new neighboring cells which UE may consider forsubsequent switch of the reception of a high-speed data flow.

In still further accord with the fourth aspect of the present invention,an integrated circuit is provided for installation in said userequipment according to the fourth aspect of the present invention,wherein said integrated circuit embodies two or more of the elements ofthe user equipment according to the fourth aspect of the presentinvention, in any combination.

According to a fifth aspect of the present invention, a method forexecution in a system comprising a radio access network (RAN) able tocommunicate with user equipment (UE), comprises the steps of sending asignal indication from said UE to said RAN that the UE wants to switchreception of a high-speed data flow from a source cell to reception fromanother, target cell, receiving in said RAN said signal indication fromsaid UE that it wants to switch reception of said high-speed data flowfrom said source cell to reception from said target cell, and inresponse thereto, said RAN sending an acknowledgement message to saidUE, said UE receiving said acknowledgement message from the RAN, saidRAN switching transmission of said data flow to the UE from said sourcecell to said target cell, said UE switching reception of said data flowfrom said source cell to said target cell after a predetermined timeperiod after receipt of said acknowledgement message, said RAN sendingto the UE a reconfiguration message via said target cell a messagecontaining an indication that informs the UE to keep a pre-configuredconfiguration or containing an indication of a new or partly newconfiguration, which the RAN prefers over the pre-configuredconfiguration, and in response thereto, said UE receiving saidreconfiguration message from said RAN containing said indication thatinforms the user equipment to keep said pre-configured configuration orcontaining an indication of said new or partly new configuration, whichthe RAN prefers over the pre-configured configuration, and in responsethereto, said UE sending a reconfiguration complete message to the RAN.

In further accord with the fifth aspect of the present invention, theindication that informs the UE to keep a pre-configured configuration orcontaining an indication of a new or partly new configuration, which theRAN prefers over the pre-configured configuration, comprises possiblenew neighboring cells which UE may consider for subsequent switch of thereception of a high-speed data flow.

In still further accord with the fifth aspect of the present invention,the system method further comprises the step of said RAN waiting apredetermined period of time between said receiving said signalindication from said UE that it wants to switch reception of saidhigh-speed data flow and said switching said transmission of said dataflow from said source cell to said target cell.

According to a sixth aspect of the present invention, a systemcomprising a radio access network (RAN) able to communicate with userequipment (UE), further comprises a device for sending a signalindication from said UE to said RAN that the UE wants to switchreception of a high-speed data flow from a source cell to reception fromanother, target cell, a device for receiving in said RAN said signalindication from said UE that it wants to switch reception of saidhigh-speed data flow from said source cell to reception from said targetcell, and in response thereto, said RAN sending an acknowledgementmessage to said UE, said UE having a device for receiving saidacknowledgement message from the RAN, said RAN having a device forswitching transmission of said data flow to the UE from said source cellto said target cell, said UE having a device for switching reception ofsaid data flow from said source cell to said target cell after apredetermined time period after receipt of said acknowledgement message,said RAN having a device for sending to the UE a reconfiguration messagevia said target cell a message containing an indication that informs theUE to keep a pre-configured configuration or containing an indication ofa new or partly new configuration, which the RAN prefers over thepre-configured configuration, and possible new neighboring cells whichUE shall consider for subsequent switch of the reception of a high-speeddata flow, and in response thereto, said UE having a device forreceiving said reconfiguration message from said RAN containing saidindication that informs the user equipment to keep said pre-configuredconfiguration or containing an indication of said new or partly newconfiguration, which the RAN prefers over the pre-configuredconfiguration, and possible new neighboring cells which UE shallconsider for subsequent switch of the reception of a high-speed dataflow, and in response thereto, said UE having means for sending areconfiguration complete message to the RAN.

In further accord with the sixth aspect of the present invention, theindication that informs the UE to keep a pre-configured configuration orcontaining an indication of a new or partly new configuration, which theRAN prefers over the pre-configured configuration, comprises possiblenew neighboring cells which UE may consider for subsequent switch of thereception of a high-speed data flow.

In still further accord with the sixth aspect of the present invention,said RAN further comprises a device for waiting a predetermined periodof time between said receiving said signal indication from said UE thatit wants to switch reception of said high-speed data flow and saidswitching said transmission of said data flow from said source cell tosaid target cell.

These and other objects, features and advantages of the presentinvention will become more apparent in light of the following detaileddescription of a best mode embodiment thereof, as illustrated in theaccompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows signaling (light lines) and data (heavy lines), accordingto the present invention.

FIG. 2 shows a system, according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIG. 1, a UE 12 is shown receiving an HS-DSCH datatransmission on a wireless HSDPA downlink 14 a from a source Node B 16(sometimes called a base station) which in turn receives the datatransmission on a hardwired line 20 a from a radio network controller22. The UE is making measurements of the strength of beacons fromneighboring cells in case the source Node B's signal becomes weak and astronger signal becomes available. The UE sends measurement reports, asshown on a line 40 via the Node B 16 to the RNC 22. The RNC 22 and thesource Node B 16 form parts of a radio access network (RAN), calledUTRAN in 3G. Although disclosed in the 3GPP (Third GenerationPartnership Project) context at its current developmental stage, itshould be realized that the invention is generally applicable totelecommunications and is not limited to the 3GPP or even to mobilecommunications.

Referring back to FIG. 1, the UE 12 is able to conduct measurements ofthe strength of the beacons from the various Node Bs 24. If itdetermines that the current source Node B 16 has a beacon signal that isweakening as compared to another Node B such as the Node B 26, it maydecide, as indicated in a measurement report signal provided on a line40 to the RNC 22, that the other Node B 26 should become its source forthe data flow provided from the RNC. In that case, the other Node B 26becomes a so-called target Node B until a changeover is made to its newrole as the source Node B. As shown in FIG. 1, the current source Node B16 may send a signal on a line 42 to the RNC 22 indicative of a numberof HARQ (Hybrid Automatic Repeat reQuest) retransmissions.

Referring to FIG. 2, the UE 12 is shown having a device 46 for sendinghandover information on the line 40 a to the RNC 22 via the Node B 16.In FIG. 2, the source Node B 16 and the target Node B are lumpedtogether in a single block labeled “Node Bs” (sometimes called “Nodes B”in the plural sense) with the reference numeral 24. The illustration ofFIG. 2 shows the measurement report, which may be an E-DCH (EnhancedDedicated Channel) measurement report, broken up into two parts, 40 a,40 b. This is because the source Node B 16 includes a signal processor48 which is responsive to the first part of the measurement reportsignal on a line 40 a representing wireless signaling, which may beL1/2/3 signalling according to future developments. In any event, thesignal processor 48 is responsive to the handover information providedon the uplink wireless line 40 a, processes the information, andprovides the handover information as a signal on a hardwired line 40 bto a device 50 in the RNC 22 for receiving handover information from theUE/Node B. The device 50 may also include a signal processor forevaluating the measurement report. The UE may have the role of decidinga handover, or that decision may instead be made in the Node B or RNC;or it may be a joint decision, as the case may be. In any event, thedevice 50 provides a signal on a line 54 to a predefined timer 56 which,in response thereto, starts a timing of a predefined time duration.After the timer times out, it sends a timeout signal on a line 58 to thedevice 28 for sending data to the UE. The device 28 of the RNC 22 isresponsive to the timeout signal and in response thereto sends the dataflow on the line 20 to the target Node B 26 instead of the source Node B16. In other words, it performs a handover function from sending to theNode B 16 to the Node B 26. This constitutes part of the handover of thedata flow in the sense just described, where the target Node B 26becomes the recipient of the data instead of the former source Node B16. In such a case, the target Node B 26 then becomes and takes on therole of the source Node B for so long as its signal strength remainsstrong, depending on the geographic movements of the UE 12. It may alsobe the case that the signal on the line 54 from the device 50 to thetimer 56 in the RNC may also be provided to the UE on a line 54 a viathe original source Node B 16. In that case, a similar timer 62 withinthe UE 12 is responsive to a signal on a line 54 b and starts a timeoutperiod similar to the period timed by the timer 56 in the RNC. Once thepredefined timer 62 times out, a timeout signal is provided on a line 64to the device 34 which indicates to the device 34 that the data flow isnow to be received on the line 14 b (as best seen in FIG. 1) from thetarget Node B 26 rather than the source Node B 16.

Referring back to FIG. 1, the signal on the line 54 b from the sourceNode B 16 to the UE 12 may be characterized as an acknowledgement signalfrom the source Node B 16 to the UE 12 and, as previously describedabove, may result directly in the start of the predefined timer 62indicating when to begin to receive the transmission from the other NodeB, i.e., the target Node B 26 in the other cell. The reception of thedata flow from the target Node B 26 is shown by an HSDPA downlinkinterface on a line 14 b in FIG. 1 where the indicated transmission is aHS-DSCH transmission to a UE reception window. Reception of the newframes in the new cell is shown occurring after the timer 62 has timedout. FIG. 1 shows the device of FIG. 2 34 receiving the data from thetarget Node B 26 and the reception of this data then continues asindicated by a reference numeral 70 in FIG. 1.

In the description which follows of the inventive configuration message,it should be noted that the delivery and timing of the configurationmessage is not necessarily distinct from the HS-DSCH transmission ofuser data on the line 14 b but is rather shown that way as separatesignals for the purposes of clarity. In like manner, the device 34 ofFIG. 2 for receiving data from the RAN and the device 102 forreceiving/sending reconfiguration information need not be distinctdevices as shown but can be combined into a single device such as asignal processor. Referring back to FIG. 1, and the fact that it has tobe understood that the signal on the line 14 b does not necessarily onlycontain plain user data but may also carry any of the configurationmessages on lines with the reference numeral 90, it will be realizedthat the RNC should send the reconfiguration signal information as fastas possible to the user equipment via the target cell or the Node Bs 24,i.e., immediately when the user equipment has started to listen to thetarget cell.

According to the present invention, a configuration message 20 b, e.g.,a physical channel reconfiguration message, is shown in FIG. 1 beingprepared for transmission from the RNC 22 via the target Node B 26 tothe UE 12. As indicated, the message can include an indication that thepre-defined configuration can be kept (dual information element) or aset of new information elements is provided for the new configuration asa normal release 5/6 reconfiguration procedure with the serving HS-DSCHcell change. An indication may be provided of a new or partly newconfiguration, which the radio access network prefers over thepre-configured configuration. It could for instance contain anindication of possible new neighboring cells which the user equipmentmay or shall consider for a subsequent switch in reception of ahigh-speed data flow. This configuration message is shown transmitted asa signal on a line 90 a from the RNC 22 via the target Node B 26 to theUE 12. In FIG. 2 the RNC is shown having a device 100 for sending theconfiguration message on the line 90 a 1 to the target Node B 26 shownin FIG. 2 within the “Node Bs” 24. A signal processor 92 receives theconfiguration message on the line 90 a 1, processes it, and provides theprocessed configuration message on the HSDPA downlink 90 a 2 from thetarget Node B 26 to a device 102 for receiving configuration informationwithin the UE 12. As mentioned, the message on the line 90 a may containan indication of a new or partly new configuration, which the radioaccess network prefers over the pre-configured configuration, which mayindicate possible new neighboring cells which the user equipment may orshall consider for a subsequent switch in reception of said high-speeddata flow. The device 102 processes the configuration message and sendsa reconfiguration complete message on the line 90 b 1 to the signalprocessor 92 within the target Node B 26 which in turn forwards it on ahardwired line 90 b 2 to the device 100 within the RNC 22. The messageon the lines 90 b 1, 90 b 2 may include an indication of a new or partlynew configuration, which as mentioned the radio access network indicatedit prefers over the pre-configured configuration, comprising possiblenew neighboring cells which the UE may consider for subsequent switch ofthe reception of a high-speed data flow. The device 100 is able toreceive reconfiguration information either indicating that theconfiguration is complete using the configuration sent on the line 90 a1 or that a new configuration has been selected by the UE and signaledon the line 90 b 2 back to the device 100 within the RNC 22.

Thus, when UTRAN receives the indication on the line 40 which may be alayer 3 (L3) message (L1/L2 indications are also possible) from the UE12 that it wants to switch the HS-DSCH reception to the other cell inthe active set (AS), the UTRAN sends a reconfiguration message on theline 90 a (FIG. 1) via the Node B 26 in a target cell (or in case ofbi-casting via both the target and source cells). The reconfigurationmessage can be either on a physical channel—transport channel—or radiobearer reconfiguration message or active set update message. Thismessage can only contain a new indication that informs the UE to keepthe configuration that is previously pre-configured for further use (forthe source cell which UE is currently using) or include a completely newor partly new configuration, which UTRAN prefers in this situation overthe pre-configured configuration and possible new neighboring cellswhich UE shall consider for subsequent switch of the reception of ahigh-speed data flow,. After receiving the configuration message the UEacts on the reconfiguration message as defined in Rel5/6 and respondswith the normal reconfiguration complete message.

From the L3 point of view the mobility procedures are kept as they arecurrently but a new possibility to signal reconfiguration via apre-configured cell is given.

It should be noted that the functional blocks shown in FIG. 2 can becarried out by software, firmware, hardware, or any combination thereofas will be appreciated by those of skill in the art. For instance, anintegrated circuit can be provided that combines one or more of thefunctions shown for installation in either the user equipment, the radionetwork controller, the Node B or the like. As will also be appreciatedby those of skill in the art, some or all of the functions not carriedout in hardware can be carried out in software whereby instructionscoded according to a selected programming language are written forexecution on a signal processor which may include a central processingunit (CPU) that is able to execute such instructions which are retrievedfrom a memory device resident in the user equipment or network element.Inasmuch as the various functions and means for carrying out thefunctions have been described in a general way, it will be appreciatedthat these functions can be combined in any way as separable softwareand hardware elements which altogether carryout the claimed invention.

It has already been mentioned that the various devices shown in FIG. 2may be carried out by means of software executed on a signal processorsuch as that of the signal processors 48, 32, 92 shown in the Node B 24or within a single equivalent signal processor within the Node B 24.Such a signal processor 92 is shown in detail in FIG. 2 as comprising anumber of components including a read only memory, a random accessmemory, a central processing unit, a clock, input/output device, andother devices all interconnected by data, address and control lines aswill be appreciated by one of skill in the art for carrying out one ormore of the methodological steps as needed to produce the signallingshown to or from any of the devices of FIG. 1. It will also beappreciated that the separate devices shown in the RNC 22 and theseparate devices shown in the user equipment 12 may also be implementedin software carried out by a signal processor within the RNC 22 and/orthe user equipment 12. Similarly, such signal processors may be carriedout as integrated circuits instead of the general purpose signalprocessor shown in FIG. 2, in other words as dedicated signalprocessors.

Although the invention has been shown and described with respect to abest mode embodiment thereof, it should be understood by those skilledin the art that the foregoing and various other changes, omissions andadditions in the form and detail thereof may be made therein withoutdeparting from the spirit and scope of the invention.

1. Method for execution in a radio access network, comprising: receivinga signal indication from a user equipment that it wants to switchreception of a high-speed data flow from a source cell to reception fromanother, target cell, and in response thereto, switching transmission ofsaid data flow to the user equipment from said source cell to saidtarget cell, sending to the user equipment a reconfiguration message viasaid target cell said message containing an indication that informs theuser equipment to keep a pre-configured configuration or containing anindication of a new or partly new configuration, which the radio accessnetwork prefers over the pre-configured configuration, and in responsethereto, receiving from the user equipment a reconfiguration completemessage.
 2. The method of claim 1, wherein the indication of a new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, contains possible new neighboringcells which the user equipment may consider for a subsequent switch inreception of said high-speed data flow.
 3. The method of claim 1,further comprising: waiting a predetermined period of time between saidreceiving said signal indication from said user equipment that it wantsto switch reception of said high-speed data flow and said switching saidtransmission of said data flow from said source cell to said targetcell.
 4. The method of claim 1, further comprising also sending saidreconfiguration message via said source cell so that saidreconfiguration message is bi-cast to said user equipment from both saidsource cell and said target cell.
 5. The method of claim 1, furthercomprising also sending said reconfiguration message to said userequipment and including a new pre-configuration of a new neighboringcell that said user equipment shall further consider as a target cellfor a subsequent switch in reception of said high-speed data flow. 6.Radio access network, comprising: device for receiving a signalindication from a user equipment that it wants to switch reception of ahigh-speed data flow from a source cell to reception from another,target cell; switching device, responsive to said signal indication fromsaid user equipment, for switching transmission of said data flow to theuser equipment from said source cell to said target cell; device forsending to the user equipment a reconfiguration message via said targetcell a message containing an indication that informs the user equipmentto keep a pre-configured configuration or containing an indication of anew or partly new configuration, which the radio access network prefersover the pre-configured configuration, and for receiving, in response tosaid reconfiguration message, a reconfiguration complete message fromthe user equipment.
 7. The radio access network of claim 6, wherein theindication of a new or partly new configuration, which the radio accessnetwork prefers over the pre-configured configuration, contains possiblenew neighboring cells which the user equipment may consider for asubsequent switch in reception of said high-speed data flow.
 8. Theradio access network of claim 6, further comprising: device for waitinga predetermined period of time between said receiving said signalindication from said user equipment that it wants to switch reception ofsaid high-speed data flow and said switching said transmission of saiddata flow from said source cell to said target cell.
 9. The radio accessnetwork of claim 6, wherein said device for sending to the userequipment said reconfiguration message is also for sending saidreconfiguration message via said source cell so that saidreconfiguration message is bi-cast to said user equipment from both saidsource cell and said target cell.
 10. Method for execution in userequipment, comprising: sending a signal indication to a radio accessnetwork that the user equipment wants to switch reception of ahigh-speed data flow from a source cell to reception from another,target cell, receiving an acknowledgement message from the radio accessnetwork, switching reception of said data flow from said source cell tosaid target cell after a predetermined time period after receipt of saidacknowledgement message, receiving a reconfiguration message from saidradio access network containing an indication that informs the userequipment to keep a pre-configured configuration or containing anindication of a new or partly new configuration, which the radio accessnetwork prefers over the pre-configured configuration, and in responsethereto, sending a reconfiguration complete message to the radio accessnetwork.
 11. The method of claim 10, wherein the indication of a new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, contains possible new neighboringcells which the user equipment may consider for a subsequent switch inreception of said high-speed data flow.
 12. User equipment, comprising:device for sending a signal indication to a radio access network thatthe user equipment wants to switch reception of a high-speed data flowfrom a source cell to reception from another, target cell; device forreceiving an acknowledgement message from the radio access network;device for switching reception of said data flow from said source cellto said target cell after a predetermined time period after receipt ofsaid acknowledgement message; and device for receiving a reconfigurationmessage from said radio access network containing an indication thatinforms the user equipment to keep a pre-configured configuration orcontaining an indication of a new or partly new configuration, which theradio access network prefers over the pre-configured configuration, andin response thereto, for sending a reconfiguration complete message tothe radio access network.
 13. The user equipment of claim 12, whereinthe indication of a new or partly new configuration, which the radioaccess network prefers over the pre-configured configuration, containspossible new neighboring cells which the user equipment may consider fora subsequent switch in reception of said high-speed data flow. 14.Method for execution in a system comprising a radio access network ableto communicate with user equipment, comprising the steps of: sending asignal indication from said user equipment to said radio access networkthat the user equipment wants to switch reception of a high-speed dataflow from a source cell to reception from another, target cell,receiving in said radio access network said signal indication from saiduser equipment that it wants to switch reception of said high-speed dataflow from said source cell to reception from said target cell, and inresponse thereto, said radio access network sending an acknowledgementmessage to said user equipment, said user equipment receiving saidacknowledgement message from the radio access network, said radio accessnetwork switching transmission of said data flow to the user equipmentfrom said source cell to said target cell, said user equipment switchingreception of said data flow from said source cell to said target cellafter a predetermined time period after receipt of said acknowledgementmessage, said radio access network sending to the user equipment areconfiguration message via said target cell a message containing anindication that informs the user equipment to keep a pre-configuredconfiguration or containing an indication of a new or partly newconfiguration, which the radio access network prefers over thepre-configured configuration, and in response thereto, said userequipment receiving said reconfiguration message from said radio accessnetwork containing said indication that informs the user equipment tokeep said pre-configured configuration or containing an indication ofsaid new or partly new configuration, which the radio access networkprefers over the pre-configured configuration, and in response thereto,said user equipment sending a reconfiguration complete message to theradio access network.
 15. The method of claim 14, wherein the indicationof a new or partly new configuration, which the radio access networkprefers over the pre-configured configuration, contains possible newneighboring cells which the user equipment may consider for a subsequentswitch in reception of said high-speed data flow.
 16. The method ofclaim 14, further comprising the step of said radio access networkwaiting a predetermined period of time between said receiving saidsignal indication from said user equipment that it wants to switchreception of said high-speed data flow and said switching saidtransmission of said data flow from said source cell to said targetcell.
 17. System comprising a radio access network able to communicatewith user equipment, further comprising: device for sending a signalindication from said user equipment to said radio access network thatthe user equipment wants to switch reception of a high-speed data flowfrom a source cell to reception from another, target cell, device forreceiving in said radio access network said signal indication from saiduser equipment that it wants to switch reception of said high-speed dataflow from said source cell to reception from said target cell, and inresponse thereto, said radio access network sending an acknowledgementmessage to said user equipment, said user equipment further comprising adevice for receiving said acknowledgement message from the radio accessnetwork, said radio access network further comprising a device forswitching transmission of said data flow to the user equipment from saidsource cell to said target cell, said user equipment further comprisinga device for switching reception of said data flow from said source cellto said target cell after a predetermined time period after receipt ofsaid acknowledgement message, said radio access network furthercomprising a device for sending to the user equipment a reconfigurationmessage via said target cell a message containing an indication thatinforms the user equipment to keep a pre-configured configuration orcontaining an indication of a new or partly new configuration, which theradio access network prefers over the pre-configured configuration, andin response thereto, said user equipment further comprising a device forreceiving said reconfiguration message from said radio access networkcontaining said indication that informs the user equipment to keep saidpre-configured configuration or containing an indication of said new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, and in response thereto, and a devicefor sending a reconfiguration complete message to the radio accessnetwork.
 18. The system of claim 17, wherein the indication of a new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, contains possible new neighboringcells which the user equipment may consider for a subsequent switch inreception of said high-speed data flow.
 19. The system of claim 17, saidradio access network further comprising means for waiting apredetermined period of time between said receiving said signalindication from said user equipment that it wants to switch reception ofsaid high-speed data flow and said switching said transmission of saiddata flow from said source cell to said target cell.
 20. Computerprogram stored in coded form on a computer readable medium for executingthe steps of claim
 1. 21. Integrated circuit for installation in saidradio access network of claim 6 embodying two or more of the elementsthereof in any combination.
 22. Computer program stored in coded form ona computer readable medium for executing the steps of claim
 10. 23.Integrated circuit for installation in said user equipment of claim 12embodying two or more of the elements thereof in any combination. 24.Radio access network, comprising: means for receiving a signalindication from a user equipment that it wants to switch reception of ahigh-speed data flow from a source cell to reception from another,target cell; means responsive to said signal indication from said userequipment, for switching transmission of said data flow to the userequipment from said source cell to said target cell; means for sendingto the user equipment a reconfiguration message via said target cell amessage containing an indication that informs the user equipment to keepa pre-configured configuration or containing an indication of a new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, and for receiving, in response to saidreconfiguration message, a reconfiguration complete message from theuser equipment.
 25. The radio access network of claim 24, furthercomprising: means for waiting a predetermined period of time betweensaid receiving said signal indication from said user equipment that itwants to switch reception of said high-speed data flow and saidswitching said transmission of said data flow from said source cell tosaid target cell.
 26. The radio access network of claim 24, wherein saidmeans for sending to the user equipment said reconfiguration message isalso for sending said reconfiguration message via said source cell sothat said reconfiguration message is bi-cast to said user equipment fromboth said source cell and said target cell.
 27. User equipment,comprising: means for sending a signal indication to a radio accessnetwork that the user equipment wants to switch reception of ahigh-speed data flow from a source cell to reception from another,target cell; means for receiving an acknowledgement message from theradio access network; means for switching reception of said data flowfrom said source cell to said target cell after a predetermined timeperiod after receipt of said acknowledgement message; and means forreceiving a reconfiguration message from said radio access networkcontaining an indication that informs the user equipment to keep apre-configured configuration or containing an indication of a new orpartly new configuration, which the radio access network prefers overthe pre-configured configuration, and in response thereto, for sending areconfiguration complete message to the radio access network.